# Elapsed Time Ruler Worksheets

Elapsed time is how much time that takes place between two events of interest. You are basically calculating the different between those two time periods. This is not as straight forward as your basic subtraction problem because time is not a base ten principal. Time is measured in units of 12-hour (non-military version) periods and 60-minute chunks. Because of this students will often get a bit off target. We use a strategy here to help students make quick work of this concept. If that strategy does not sit well with your students, check the bottom of this page for a different technique that may work better for you. In this selection of worksheets and lessons students learn the concept of elapsed time and how to determine it with the help of a ruler.

### Aligned Standard: Grade 3 Measurement - 3.MD.A.1

- Printable Elapsed Time Ruler- This is the perfect guide for you through this entire section. This tool can be very valuable for speeding up your ability to determine how much time has elapsed over the course of one day.
- Step-by-step Lesson- This one does not have loose increment. This documents exactly how to use this tool by walking you through finding the time between 3:45 am and 6:30 am using the ruled timeline.
- Guided Lesson - We get into the concept of having more than standard increments here.
- Guided Lesson Explanation - You can draw these up as differences as well. I put that in there, in case you teach it that way.
- Practice Worksheet 1 - You're on your own now. 4 problems for you to manage.
- Practice Worksheet 2 - You are asked to use the ruler that is provided to determine a total of 4 elapsed times. More practice for you!

- Answer Keys - These are for all the unlocked materials above.

### Practice Worksheets

It's more focused on reading times here. Make sure that you clearly understand where it started and where it ended.

- Practice 3 - The morning times are found on top. Night times on the bottom.
- Practice 4 - a.m. stands for ante meridiem which is a Latin phrase which translates as "before noon".
- Practice 5 - p.m. stands for post meridiem and translates as "after midday".
- Practice 6 - You can really go through life without ever understanding the mean of those two.
- Practice 7 - Before noon up top and afternoon down below.
- Practice 8 - See how you do with this time differences.
- Practice 9 - We space things out in 10 minute slices.

### What is the Concept of Elapsed Time?

You have to go to a party at 8 pm and you are supposed to go shopping with your best friend at 6 pm. But before you go for shopping you need to clean your room, do laundry and dishes. Now, will you plan how to manage these things within the given time? Or will you start getting things done, unplanned, wising that you do it all in time?

The amount of time from the start of an event to its end is known as Elapsed time. To be more precise, the elapsed time can be defined as the time from one time (6 pm) to another time (8 pm).

A clock is an essential tool when it comes to measuring time. If you canâ€™t make sense of an analog clock this concept is going to give you a hard time. Since we do not use the traditional base ten system to measure time, it can often give students some difficulty. Here what you need to know before you move on to calculating the time that has elapsed.

- The shorter had on the clock is the hour hand. That measure coincides directly with the 12 numbers on the clock. The number this hand points to or between is hour.

- The more extended hand on the clock is the minute hand. Each number on the clock is equal to five minutes on the clock.

- We look at the hour hand first and then at minute hand to measure time.

- There may also be a second hand on some analog clocks. This is the fast-moving hand and covers 60 locations every minute. Each location is equal to a second.

### How to Teach the Elapsed Time

If you followed along with the lessons and worksheets above, you will see that I recommend teaching this concept as an extension to a timeline. This is a skill that students have explored across just about all the major subject areas. They are very receptive to this as a whole. I have had great success with approaching it from this angle, but there are always a few students that struggle. What are you supposed to do for them?

There is another strategy that works well with students that grapple with the timeline technique. It centers around using the T-chart. This is similar to the timeline but presents the information in a different way. This strategy definitely favors students that have strong rounding and addition skills. As you will see in the setup diagram below, of a T-chart that starts at 3:35 pm and ends at 6:50 pm. You begin by balancing the hours difference between the start and end time. You then state the time that you have jumped to achieve this. You then do the same thing for the minutes. The elapsed time is just the sum of those two values. In this case, 3 hours and 15 minutes.